The present invention generally relates to a method for delivering substances such as drugs, vaccines and the like used in the prevention, diagnosis, alleviation, treatment, or cure of diseases into the skin of an animal using an injection device having a needle cannula and a limiter for engaging the surface of the skin and limiting penetration of the tip of the needle cannula into the skin, and more specifically to a method for injecting such substances intradermally, i.e., preferably from approximately 1.0 mm to approximately 2.0 mm, and most preferably around 1.5 mmxc2x10.2 mm to 0.3 mm, such that the substance is injected into the dermis layer of the animal. In addition, the method of the present invention includes fixing the orientation of the needle cannula, i.e., so that the needle cannula is preferably generally perpendicular to the plane of the skin engaging surface of the limiter within about fifteen degrees, and the skin engaging surface is generally flat.
Intradermal injections are used for delivering a variety of substances. Many of these substances have proven to be more effectively absorbed into or react with the immune response system of the body when injected intradermally. Recently, clinical trials have shown that hepatitis B vaccines administered intradermally are more immunogenic than if administered intramuscularly. In addition, substances have been injected intradermally for diagnostic testing, such as, for example using what is known in the art as the xe2x80x9cMantoux testxe2x80x9d to determine the immunity status of the animal against tuberculosis and the immediate hypersensitivity status of Type I allergic diseases.
An intradermal injection is made by delivering the substance into the epidermis and upper layers of the dermis. Below the dermis layer is subcutaneous tissue (also sometimes referred to as the hypodermis layer) and muscle tissue, in that order. There is considerable variation in the skin thickness both between individuals and within the same individual at different sites of the body. Generally, the outer skin layer, epidermis, has a thickness between 50-200 microns, and the dermis, the inner and thicker layer of the skin, has a thickness between 1.5-3.5 mm. Therefore, a needle cannula that penetrates the skin deeper than about 3.0 mm has a potential of passing through the dermis layer of the skin and making the injection into the subcutaneous region, which may result in an insufficient immune response, especially where the substance to be delivered intradermally has not been indicated for subcutaneous injection. Also, the needle cannula may penetrate the skin at too shallow a depth to deliver the substance and result in what is commonly known in the art as a xe2x80x9cwet injectionxe2x80x9d because of reflux of the substance from the injection site.
The standard procedure for making an intradermal injection is known to be difficult to perform, and therefore dependent upon experience and technique of the healthcare worker. This procedure is recommended to be performed by stretching the skin, orienting the bevel of a 26 Gauge short bevel needle cannula upwardly and inserting the needle cannula to deliver a volume of 0.5 ml or less of the substance into the skin of an animal with the needle cannula being inserted into the skin at an angle varying from around 10-15 degrees relative to the plane of the skin to form a blister or wheal in which the substance is deposited or otherwise contained. Accordingly, the technique utilized to perform the standard intradermal injection is difficult and requires the attention of a trained nurse or medical doctor. This procedure also makes it essentially impossible to self-administer an intradermal injection. Inserting the needle to a depth greater than about 3.0 mm typically results in a failed intradermal injection because the substance being expelled through the cannula will be injected into the subcutaneous tissue of the animal. Further, the present method is not suitable for self-administration of intradermal injections.
The most frequent cause of a failed intradermal injection is derived from inserting the needle into the skin at an angle greater than 15 degrees. A further cause of error is derived from pinching rather than stretching the skin in the area of the injection, which is normally done when giving a subcutaneous rather than an intradermal injection. Pinching increases the likelihood of giving a subcutaneous injection. Procedural errors as described above result in delivering the contents of the injection into the subcutaneous layer, which can reduce the effectiveness of the injection, as well as possibly deliver the substance in a way not approved for delivery. Intradermal injections performed by using the standard procedure also are known to cause a significant amount of pain to the recipient of the injection because the needle cannula is inserted into the skin at an angle of about 10-15 degrees. By inserting the needle cannula at this angle, about 5 mm to about 6 mm of the needle is actually inserted into the skin. This results in a significant disruption of the pain receptors dispersed throughout the upper layers of the skin.
Accordingly, there has been a long felt need for a simplified method of performing an intradermal injection of substances which overcomes the problems and limitations associated with conventional methods, especially including reducing the probability of error and pain caused from the injection by making such injections less dependent upon experience and technique. In addition, there has been a need to limit the depth of penetration of the needle cannula into the skin of the animal to avoid entry into the subcutaneous layer of the skin as well as reliably fixing the orientation of the needle cannula relative to the skin. Also, there has been a need to apply pressure to the skin of the animal to facilitate formation of the blister or wheal in the skin in which the substance is deposited or otherwise contained and avoid wet injections.
In contrast to the conventional methods discussed above, it has been found by the applicant that a method of intradermally injecting substances into the skin can be used in accordance with the present invention to effectively and reliably deliver such substances intradermally. Specifically, the method includes fixing the orientation of the needle cannula relative to the skin and engaging the surface of the skin to limit the depth of penetration of the needle cannula into the skin, i.e., preferably from approximately 1.0 mm to approximately 2.0 mm, and most preferably around 1.5 mmxc2x10.2 mm to 0.3 mm, to avoid entry into the subcutaneous layer. In addition, the method includes applying pressure to the surface of the skin to facilitate delivery of the substance, particularly formation of a blister or wheal in the skin in which the substance is deposited or otherwise contained. Further, the pressure applied masks the pain derived from the intradermal injection by stimulating the muscle fibers to block the pain receptors. Many substances have proven to be more effective when injected intradermally in the prevention, diagnosis, alleviation, treatment, or cure of diseases. These include several drugs and vaccines such as, for example, influenza vaccines, hepatitis B vaccine, rabies vaccines tuberculin test substance and many others. These vaccines, drugs and the like will hereinafter be referred to as substances. It is also possible to self-administer intradermal injections by the method of this invention.
The hypodermic needle assembly set forth above includes the elements necessary to perform the present invention directed to an improved method of making an intradermal injection into the skin of an animal including the steps of providing a drug delivery device including a needle cannula having a forward needle tip and the needle cannula being in fluid communication with a substance contained in the drug delivery device and including a limiter portion surrounding the needle cannula and the limiter portion including a skin engaging surface, with the needle tip of the needle cannula extending from the limiter portion beyond the skin engaging surface a distance equal to approximately 0.5 mm to approximately 3.0 mm and the needle cannula having a fixed angle of orientation relative to a plane of the skin engaging surface of the limiter portion, inserting the needle tip into the skin of an animal and engaging the surface of the skin with the skin engaging surface of the limiter portion, such that the skin engaging surface of the limiter portion limits penetration of the needle cannula tip into the dermis layer of the skin of the animal, and expelling the substance from the drug delivery device through the needle cannula tip into the skin of the animal.
In the preferred method, the substance is selected from the group consisting of drugs, vaccines and the like used in the prevention, diagnosis, alleviation, treatment, or cure of diseases. In addition, the fixed angle of orientation of the needle cannula is further defined as being generally perpendicular to the plane of the skin engaging surface of the limiter portion within about fifteen degrees, and most preferably within about five degrees, substantially ninety degrees relative to the plane of the skin engaging surface of the limiter portion. In addition, the drug delivery device includes a syringe having a barrel and a plunger rod preferably including a stopper received within the barrel therein and the plunger rod being depressable to expel the substance from the delivery device through the tip of the needle cannula, with the barrel including a barrel tip and the needle cannula forms part of a needle assembly attachable to and in fluid communication with the barrel tip.
Also, the preferred embodiment of the method includes the step of selecting an injection sight on the skin of the animal and includes the step of cleaning the injection sight on the skin of the animal prior to expelling the substance from the drug delivery device into the skin of the animal. In addition, the method includes the step of filling the drug delivery device with the substance. Further, the method includes the steps of pressing the skin engaging surface of the limiter portion against the skin of the animal and applying pressure, thereby stretching the skin of the animal, and withdrawing the needle cannula from the skin after injecting the substance. Still further, the step of inserting the forward tip into the skin is further defined by inserting the forward tip into the skin to a depth of from approximately 1.0 mm to approximately 2.0 mm, and most preferably into the skin to a depth of 1.5 mmxc2x10.2 to 0.3 mm. The preferred substance comprises an influenza vaccine, a hepatitis B vaccine, a rabies vaccine, a cancer vaccine, a genetic based vaccine or a tuberculin test substance.
In addition, the present invention is directed to a method of making an intradermal injection with a drug delivery device having a limiter with a skin engaging surface limiting the depth a needle cannula can be inserted into the skin of an animal including the steps of exposing a forward tip of the needle cannula extending from a limiter beyond a skin engaging surface a distance equal to approximately 0.5 mm to approximately 3.0 mm and the needle cannula having a fixed angle of orientation relative to the skin engaging surface of the limiter, inserting the forward tip of the needle cannula into the skin of the animal at until the skin engaging surface contacts the skin of the animal, and expelling a substance from the device into the dermis layer of the skin of the animal.
In the preferred embodiment of the method, the step of inserting the forward tip into the skin of the animal is further defined by inserting the forward tip into the skin at an angle being generally perpendicular to the skin within about fifteen degrees, with the angle most preferably being generally ninety degrees to the skin, within about five degrees, and the fixed angle of orientation relative to the skin engaging surface is further defined as being generally perpendicular. In the preferred embodiment, the limiter surrounds the needle cannula, having a generally planar flat skin engaging surface. Also, the drug delivery device comprises a syringe having a barrel and a plunger received within the barrel and the plunger being depressable to expel the substance from the delivery device through the forward tip of the needle cannula.
In the preferred embodiment of the method of the present invention, expelling the substance from the delivery device is further defined by grasping the hypodermic needle with a first hand and depressing the plunger with an index finger of a second hand and expelling the substance from the delivery device by grasping the hypodermic needle with a first hand and depressing the plunger on the hypodermic needle with a thumb of a second hand, with the step of inserting the forward tip into the skin of the animal further defined by pressing the skin of the animal with the limiter. In addition, the method may includes the step of attaching a needle assembly to a tip of the barrel of the syringe with the needle assembly including the needle cannula and the limiter, and includes the step of exposing the tip of the barrel before attaching the needle assembly thereto by removing a cap from the tip of the barrel. Alternatively, the step of inserting the forward tip of the needle into the skin of the animal may be further defined by simultaneously grasping the hypodermic needle with a first hand and pressing the limiter against the skin of the animal thereby stretching the skin of the animal, and expelling the substance by depressing the plunger with an index finger of the first hand or expelling the substance by depressing the plunger with a thumb of the first hand. The method further includes withdrawing the forward tip of the needle cannula from the skin of the animal after the substance has been injected into the skin of the animal. Still further, the method includes inserting the forward tip into the skin preferably to a depth of from approximately 1.0 mm to approximately 2.0 mm, and most preferably to a depth of 1.5 mmxc2x10.2 to 0.3 mm.
Also, the substance intradermally delivered in accordance with the method of the present invention is selected from the group consisting of drugs, vaccines and the like used in the prevention, diagnosis, alleviation, treatment, or cure of disease, with the drugs including Alpha-1 anti-trypsin, Anti-Angiogenesis agents, Antisense, butorphanol, Calcitonin and analogs, Ceredase, COX-II inhibitors, dermatological agents, dihydroergotamine, Dopamine agonists and antagonists, Enkephalins and other opioid peptides, Epidermal growth factors, Erythropoietin and analogs, Follicle stimulating hormone, G-CSF, Glucagon, GM-CSF, granisetron, Growth hormone and analogs (including growth hormone releasing hormone), Growth hormone antagonists, Hirudin and Hirudin analogs such as hirulog, IgE suppressors, Insulin, insulinotropin and analogs, Insulin-like growth factors, Interferons, Interleukins, Leutenizing hormone, Leutenizing hormone releasing hormone and analogs, Low molecular weight heparin, M-CSF, metoclopramide, Midazolam, Monoclonal antibodies, Narcotic analgesics, nicotine, Non-steroid anti-inflammatory agents, Oligosaccharides, ondansetron, Parathyroid hormone and analogs, Parathyroid hormone antagonists, Prostaglandin antagonists, Prostaglandins, Recombinant soluble receptors, scopolamine, Serotonin agonists and antagonists, Sildenafil, Terbutaline, Thrombolytics, Tissue plasminogen activators, TNFxe2x80x94, and TNFxe2x80x94antagonist, the vaccines, with or without carriers/adjuvants, including prophylactics and therapeutic antigens (including but not limited to subunit protein, peptide and polysaccharide, polysaccharide conjugates, toxoids, genetic based vaccines, live attenuated, reassortant, inactivated, whole cells, viral and bacterial vectors) in connection with, addiction, arthritis, cholera, cocaine addiction, diphtheria, tetanus, HIB, Lyme disease, meningococcus, measles, mumps, rubella, varicella, yellow fever, Respiratory syncytial virus, tick borne japanese encephalitis, pneumococcus, streptococcus, typhoid, influenza, hepatitis, including hepatitis A, B, C and E, otitis media, rabies, polio, HIV, parainfluenza, rotavirus, Epstein Barr Virus, CMV, chlamydia, non-typeable haemophilus, moraxella catarrhalis, human papilloma virus, tuberculosis including BCG, gonorrhoea, asthma, atheroschlerosis malaria, E-coli, Alzheimers, H. Pylori, salmonella, diabetes, cancer, herpes simplex, human papilloma and the like other substances including all of the major therapeutics such as agents for the common cold, Anti-addiction, anti-allergy, anti-emetics, anti-obesity, antiosteoporeteic, anti-infectives, analgesics, anesthetics, anorexics, antiarthritics, antiasthmatic agents, anticonvulsants, anti-depressants, antidiabetic agents, antihistamines, anti-inflammatory agents, antimigraine preparations, antimotion sickness preparations, antinauseants, antineoplastics, antiparkinsonism drugs, antipruritics, antipsychotics, antipyretics, anticholinergics, benzodiazepine antagonists, vasodilators, including general, coronary, peripheral and cerebral, bone stimulating agents, central nervous system stimulants, hormones, hypnotics, immunosuppressives, muscle relaxants, parasympatholytics, parasympathomimetrics, prostaglandins, proteins, peptides, polypeptides and other macromolecules, psychostimulants, sedatives, sexual hypofunction and tranquilizers and major diagnostics such as tuberculin and other hypersensitivity agents.
Another embodiment of the method of the present invention of making an intradermal injection into the skin of an animal includes the steps of providing a drug delivery device with a prefillable container including a needle cannula having a forward needle tip and the needle cannula being in fluid communication with a substance contained in the prefillable container and including a limiter portion surrounding the needle cannula and the limiter portion including a skin engaging surface, with the needle tip of the needle cannula extending from the limiter portion beyond the skin engaging surface and the needle cannula having a fixed angle of orientation relative to a plane of the skin engaging surface of the limiter portion, inserting the needle tip into the skin of an animal and engaging the surface of the skin with the skin engaging surface of the limiter portion such that the skin engaging surface of the limiter portion limits penetration of the needle tip into the dermis layer of the skin of the animal, and expelling the substance from the drug delivery device through the needle tip into the skin of the animal.
In yet another embodiment, the method of the present invention is directed to intradermally injecting an influenza vaccine into the skin of an animal including the steps of providing a drug delivery device including a needle cannula having a forward needle tip and the needle cannula being in fluid communication with an influenza vaccine contained in the drug delivery device and including a limiter portion surrounding the needle cannula and the limiter portion including a skin engaging surface, with the needle tip of the needle cannula extending from the limiter portion beyond the skin engaging surface a distance equal to approximately 0.5 mm to approximately 3.0 mm and the needle cannula having a fixed angle of orientation relative to a plane of the skin engaging surface of the limiter portion, inserting the needle tip into the skin of an animal and engaging the surface of the skin with the skin engaging surface of the limiter portion such that the skin engaging surface of the limiter portion limits penetration of the needle tip into the dermis layer of the skin of the animal and not into the subcutaneous tissue, and expelling the influenza vaccine from the drug delivery device through the needle tip into the dermis layer of the skin of the animal.
In the preferred embodiment of the method of intradermally injecting an influenza vaccine, the fixed angle of orientation of the needle cannula is further defined as being generally perpendicular to the plane of the planar skin engaging surface of the limiter portion, within about fifteen degrees, and most preferably the fixed angle of being ninety degrees relative to the plane of the skin engaging surface of the limiter portion within about five degrees. In addition, the method preferably includes inserting the forward tip into the skin to a depth of from approximately 1.0 mm to approximately 2.0 mm, and most preferably to a depth of 1.5 mmxc2x10.2 mm to 0.3 mm.